Revert "Temporarily Revert "Add basic loop fusion pass.""

The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552

1 files changed, 59 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopUnswitch/infinite-loop.ll b/llvm/test/Transforms/LoopUnswitch/infinite-loop.ll
new file mode 100644
index 00000000000..f11aa50e634
--- /dev/null
+++ b/llvm/test/Transforms/LoopUnswitch/infinite-loop.ll
@@ -0,0 +1,59 @@
+; REQUIRES: asserts
+; RUN: opt -loop-unswitch -disable-output -stats -info-output-file - < %s | FileCheck --check-prefix=STATS %s
+; RUN: opt -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -disable-output -stats -info-output-file - < %s | FileCheck --check-prefix=STATS %s
+; RUN: opt -loop-unswitch -simplifycfg -S < %s | FileCheck %s
+; PR5373
+
+; Loop unswitching shouldn't trivially unswitch the true case of condition %a
+; in the code here because it leads to an infinite loop. While this doesn't
+; contain any instructions with side effects, it's still a kind of side effect.
+; It can trivially unswitch on the false case of condition %a though.
+
+; STATS: 2 loop-unswitch - Number of branches unswitched
+; STATS: 2 loop-unswitch - Number of unswitches that are trivial
+
+; CHECK-LABEL: @func_16(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br i1 %a, label %entry.split, label %abort0.split
+
+; CHECK: entry.split:
+; CHECK-NEXT: br i1 %b, label %for.body, label %abort1.split
+
+; CHECK: for.body:
+; CHECK-NEXT: br label %for.body
+
+; CHECK: abort0.split:
+; CHECK-NEXT: call void @end0() [[NOR_NUW:#[0-9]+]]
+; CHECK-NEXT: unreachable
+
+; CHECK: abort1.split:
+; CHECK-NEXT: call void @end1() [[NOR_NUW]]
+; CHECK-NEXT: unreachable
+
+; CHECK: }
+
+define void @func_16(i1 %a, i1 %b) nounwind {
+entry:
+  br label %for.body
+
+for.body:
+  br i1 %a, label %cond.end, label %abort0
+
+cond.end:
+  br i1 %b, label %for.body, label %abort1
+
+abort0:
+  call void @end0() noreturn nounwind
+  unreachable
+
+abort1:
+  call void @end1() noreturn nounwind
+  unreachable
+}
+
+declare void @end0() noreturn
+declare void @end1() noreturn
+
+; CHECK: attributes #0 = { nounwind }
+; CHECK: attributes #1 = { noreturn }
+; CHECK: attributes [[NOR_NUW]] = { noreturn nounwind }